Time synchronization and punctuality method and system for low-voltage transformer area acquisition system

Abstract

The invention discloses a low-voltage transformer area acquisition system time synchronization and time keeping method and system. A terminal receives clock signals of an acquisition master station and other clock sources in real time; when a time synchronization instruction of the acquisition master station is received, the time issued by the acquisition master station is preferentially synchronized to a clock unit of the terminal, and otherwise, the next step is executed; the terminal evaluates and selects other clock sources meeting conditions as reliable clock sources according to the clock signal strength and the signal stability of continuous x days; based on the selected reliable clock source, calculating the sample density and weight of each clock source so as to obtain a standard clock through calculation; other clock sources calculate to obtain standard clock-to-terminal time synchronization; and the terminal performs time synchronization with the electric energy meter. According to the scheme, high-frequency and high-precision absolute time synchronization between the CCO and the STA is realized on the basis of not increasing hardware.

Description

Technical Field

[0001] The present invention relates to the technical field of electricity consumption information collection, and in particular to a time synchronization and timekeeping method and system for a low-voltage area side of an electricity consumption information collection system. Background Art

[0002] The perception, monitoring, and regulation of the distributed "source, network, load, storage, and charging" side of the power grid, as well as emerging business areas such as electricity spot trading, have put forward higher requirements for the real-time and synchronization of metering and collection data. Most monitoring, analysis, and control applications based on key metering / measurement data such as voltage, current, and phase angle in the power system (for example: line loss analysis, energy meter error analysis, and load monitoring) require synchronized measurement data under the same precise time reference to ensure the accuracy of intelligent data analysis results. Therefore, the accuracy and consistency requirements of the clocks of the entire link of the electricity information collection system are becoming increasingly prominent.

[0003] In the existing technical solutions, the master station is generally provided with accurate time by the system NTP timing server, the terminal side is patrolled and synchronized by the master station on a periodic basis, the electric energy meter side is directly patrolled by the master station and synchronized through transparent transmission, or the terminal performs broadcast time synchronization within the station area for the electric energy meter with a clock error within 5 minutes. If it exceeds 5 minutes, a clock deviation event is formed and reported to the master station, and the master station performs point-to-point time synchronization.

[0004] However, due to the instability of the communication channel and the influence of channel delay, the clocks of the terminals and the electric energy meters may be out of sync, and even out of tolerance. In addition, since the accuracy of the terminal clock cannot be fully ensured in actual operation, the broadcast time calibration strategy of the terminals of most power companies for the local electric energy meters is closed, and all are completed by the master station inspection and time synchronization strategy. However, since the number of terminals and electric energy meters on site has reached tens of millions or more, and the time synchronization requires the use of cipher machines, the time synchronization task pressure and key service pressure on the master station side are huge, and the master station time synchronization scheme can only carry out inspection and time synchronization work on a weekly or even half-monthly basis. Such a frequency cannot meet the various abnormalities of the battery undervoltage of various electric energy meters on site, planned and unplanned power outages, terminal and electric energy meter clock chip failures, etc., which cause out of tolerance of the terminal and electric energy meter clocks. It is necessary to manually use a handheld device to complete the on-site time synchronization of the terminal and electric energy meter through the infrared or 485 interface. The above status quo can no longer meet the requirements of policy requirements, customer needs, and new business development for the clock control of the low-voltage area acquisition system.

[0005] Chinese patent application CN116260542 discloses a clock optimization method and system for a flexible rate electric energy meter. This method of updating the node time by correcting the time information of neighboring nodes cannot solve the problem of central node clock deviation caused by unstable remote communication between the master station and the terminal or the clock deviation of the entire area caused by unstable clock source.

[0006] Chinese patent application CN113315546 discloses a time synchronization method for a low voltage area acquisition system based on HPLC carrier wave, which cannot solve the problem of terminal clock source out-of-tolerance caused by factors such as unstable remote communication between the master station and the terminal or long terminal inspection cycle of the master station. Summary of the invention

[0007] The technical problem to be solved by the present invention is how to complete the accurate time synchronization of the terminal and all electric energy meters in the area when the terminal fails to synchronize the terminal in time at the acquisition main station.

[0008] The present invention solves the above technical problems through the following technical means:

[0009] The time synchronization and time keeping method of the low voltage area acquisition system includes the following steps:

[0010] The terminal receives the clock signals from the acquisition master station and other clock sources in real time; when receiving the time synchronization instruction from the acquisition master station, it will first synchronize the time issued by the acquisition master station to the clock unit of the terminal, otherwise it will execute the next step;

[0011] Reliability evaluation and selection of other clock sources: The terminal evaluates and selects other clock sources that meet the conditions as reliable clock sources based on the clock signal strength and signal stability for x consecutive days. Based on the selected reliable clock sources, the terminal calculates the sample density and weight of each clock source to obtain the standard clock.

[0012] Other clock sources are used to calculate the standard clock to align the terminal time;

[0013] Terminal to energy meter time synchronization: The terminal synchronizes its time to the CCO according to the set period; the CCO periodically synchronizes the clock to all STAs in the local low-voltage area through the carrier NTB and the extended millisecond perpetual calendar, and expands the millisecond perpetual calendar through the built-in crystal oscillator of CCO and STA and the time slot control mechanism between CCO and STA, so as to maintain the consistency of STA and CCO clocks at high frequency; the STA synchronizes the energy meter.

[0014] Furthermore, the other clock sources include Beidou clock source, long-wave clock source, and telecommunication base station clock source; the terminal integrates Beidou timing chip, long-wave timing chip, and telecommunication base station timing chip.

[0015] Furthermore, the specific process of reliability assessment of other clock sources is as follows:

[0016] Assume that there are three types of other clock sources; the terminal monitors the signal strength of other clock sources for a long time according to the set period, and records the signal strength for x consecutive days to form signal strength sequences M1{(t 1， m 11 ), (t 2，m 12 ),(t 3， m 13 )…(t i， m 1i )…(t n， m 1n )}、M2{(t 1， m 21 ), (t 2， m 22 ),(t 3， m 23 )…(t i， m 2i )…(t n， m 2n )}、M3{(t 1， m 31 ), (t 2， m 32 ),(t 3， m 33 )…(t i， m 3i )…(t n， m 3n )}, where t i is the time series, m 1i 、m 2i 、m 3i Corresponding to t i The strength of the three types of signal sources at the moment. At the same time, the terminal continuously monitors and covers the signal strength sequence forward according to the slip time of the set period;

[0017] Define the clock signal source stability as:

[0018] in is the average value of the signal strength sequence of the first-class clock source, RSD1(j) is the stability of the first-class clock source on the jth day;

[0019] in is the average value of the signal strength sequence of the second type of clock source, RSD2(j) is the stability of the second type of clock source on the jth day;

[0020] Among them is is the average value of the signal strength sequence of the third type of clock source, RSD3(j) is the stability of the third type of clock source on the jth day;

[0021] The terminal can obtain the clock signal source stability RSD1(j) of the three types of signal sources for x consecutive days every day according to the set period slip time, i = 1, 2, 3...; when the previous clock signal source is available and the clock signal source stability of the previous x days is greater than the set values ​​of the three types of signal sources for x consecutive days, the signal source is taken as a reliable clock signal source.

[0022] Furthermore, the specific process of calculating the standard clock of other clock sources is as follows:

[0023] Assume that there are three types of reliable clock signal sources; the time T = {T1, T2, T3} of the three types of clock sources obtained by the terminal according to the set period, then the time distance between any two clock sources is defined as

[0024] Where: i, j = 1, 2, ..., n;

[0025] Define the clock source time sample density as: ρ i =N{d ij ≤ε}, where N{·} is a function for calculating the number of sample elements that meet the conditions; ε is a clock source clock error control parameter;

[0026] Define the standard clock source as: where ω i is the weight of the Ti clock source, defined as:

[0027]

[0028] When the time distance between a clock source and all other clock sources is greater than ε, ρ i =0,ω i =0, that is, the clock source has no contribution to the final timing clock.

[0029] Furthermore, STA synchronizes the electric energy meter as follows:

[0030] STA confirms whether the meter is powered off and responding during information exchange with the meter. If the interaction is normal, STA compares the timestamp carried by the meter data and calculates the time difference between the meter and STA.

[0031] If the time difference between the energy meter and the STA is greater than 5s, the STA synchronizes its clock to the energy meter clock unit and continues the monitoring and judgment strategy in the previous step according to the interaction frequency between the STA and the energy meter;

[0032] If the electric energy meter has a power outage or other abnormalities, the electric energy meter will immediately request the current time from the STA after it starts and resumes normal operation and completes the settlement-related data processing. After receiving the request, the STA will synchronize its clock to the electric energy meter clock unit.

[0033] The present invention also provides a low-voltage area acquisition system time synchronization and time keeping system, comprising:

[0034] Signal acquisition module: The terminal receives and acquires clock signals from the master station and other clock sources in real time;

[0035] The acquisition master station synchronizes the time with the terminal; when receiving the synchronization instruction from the acquisition master station, the time sent by the acquisition master station is synchronized to the clock unit of the terminal first;

[0036] Reliability evaluation and selection module for other clock sources: The terminal evaluates and selects other clock sources that meet the conditions as reliable clock sources based on the clock signal strength and signal stability for x consecutive days; based on the selected reliable clock sources, the sample density and weight of each clock source are calculated to obtain the standard clock;

[0037] Other clock sources for terminal time synchronization module: other clock sources calculate the standard clock for terminal time synchronization;

[0038] Terminal to electric energy meter timing module: The terminal synchronizes its time to CCO according to the set period; CCO periodically synchronizes the clock to all STAs in the local low-voltage area through carrier NTB and extended millisecond perpetual calendar, and expands the millisecond perpetual calendar through the built-in crystal oscillator of CCO and STA and the time slot control mechanism between CCO and STA, so as to maintain the consistency of STA and CCO clocks at high frequency; STA synchronizes the electric energy meter.

[0039] Furthermore, the other clock sources include Beidou clock source, long-wave clock source, and telecommunication base station clock source; the terminal integrates Beidou timing chip, long-wave timing chip, and telecommunication base station timing chip.

[0040] Furthermore, the specific process of reliability assessment of other clock sources is as follows:

[0041] Assume that there are three types of other clock sources; the terminal monitors the signal strength of other clock sources for a long time according to the set period, and records the signal strength for x consecutive days to form signal strength sequences M1{(t 1， m 11 ), (t 2， m 12 ),(t 3， m 13 )…(t i， m 1i )…(t n， m 1n )}、M2{(t 1， m 21 ), (t 2， m 22 ),(t 3， m 23 )…(t i， m2i )…(t n， m 2n )}、M3{(t 1， m 31 ), (t 2， m 32 ),(t 3， m 33 )…(t i， m 3i )…(t n， m 3n )}, where t i is the time series, m 1i 、m 2i 、m 3i Corresponding to t i The strength of the three types of signal sources at the moment. At the same time, the terminal continuously monitors and covers the signal strength sequence forward according to the slip time of the set period;

[0042] Define the clock signal source stability as:

[0043] in is the average value of the signal strength sequence of the first-class clock source, RSD1(j) is the stability of the first-class clock source on the jth day;

[0044] in is the average value of the signal strength sequence of the second type of clock source, RSD2(j) is the stability of the second type of clock source on the jth day;

[0045] Among them is is the average value of the signal strength sequence of the third type of clock source, RSD3(j) is the stability of the third type of clock source on the jth day;

[0046] The terminal can obtain the clock signal source stability RSD1(j) of the three types of signal sources for x consecutive days every day according to the set period slip time, i = 1, 2, 3...; when the previous clock signal source is available and the clock signal source stability of the previous x days is greater than the set values ​​of the three types of signal sources for x consecutive days, the signal source is taken as a reliable clock signal source.

[0047] Furthermore, the specific process of calculating the standard clock of other clock sources is as follows:

[0048] Assume that there are three types of reliable clock signal sources; the time T = {T1, T2, T3} of the three types of clock sources obtained by the terminal according to the set period, then the time distance between any two clock sources is defined as

[0049] Where: i, j = 1, 2, ..., n;

[0050] Define the clock source time sample density as: ρ i =N{d ij ≤ε}, where N{·} is a function for calculating the number of sample elements that meet the conditions; ε is a clock source clock error control parameter;

[0051] Define the standard clock source as: where ω i is the weight of the Ti clock source, defined as:

[0052]

[0053] When the time distance between a clock source and all other clock sources is greater than ε, ρ i =0,ω i =0, that is, the clock source has no contribution to the final timing clock.

[0054] Furthermore, STA synchronizes the electric energy meter as follows:

[0055] STA confirms whether the meter is powered off and responding during information exchange with the meter. If the interaction is normal, STA compares the timestamp carried by the meter data and calculates the time difference between the meter and STA.

[0056] If the time difference between the energy meter and the STA is greater than 5s, the STA synchronizes its clock to the energy meter clock unit and continues the monitoring and judgment strategy in the previous step according to the interaction frequency between the STA and the energy meter;

[0057] If the electric energy meter has a power outage or other abnormalities, the electric energy meter will immediately request the current time from the STA after it starts and resumes normal operation and completes the settlement-related data processing. After receiving the request, the STA will synchronize its clock to the electric energy meter clock unit.

[0058] The advantages of the present invention are:

[0059] The present invention realizes high-frequency and high-precision absolute time synchronization between CCO and STA without adding hardware. First, through the data link layer synchronization time, the influence of network instability factors such as local environmental interference on the clock synchronization accuracy is solved. Second, through the data link layer beacon frame transmission time, the high-frequency synchronization can be performed with the beacon frame, which solves the problems of low frequency of master station or terminal synchronization based on application layer, more channel resources occupied, and large concurrency of master station. Third, by using high-frequency crystal oscillator and protocol expansion, the synchronization accuracy can reach millisecond level, which is higher than the synchronization accuracy of application layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a diagram showing the time synchronization and timekeeping system architecture of the low voltage area acquisition system in an embodiment of the present invention;

[0061] Figure 2 This is a flow chart of terminal time synchronization and time keeping in an embodiment of the present invention;

[0062] Figure 3 This is a flow chart of terminal-CCO-STA-electric energy meter time synchronization and time keeping in an embodiment of the present invention;

[0063] Figure 4 It is the beacon frame structure of the existing carrier communication protocol and has the conditions for expanding the millisecond-level perpetual calendar protocol. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] This embodiment records a time synchronization and time keeping method for a low voltage area acquisition system based on multiple clock sources, which is performed in the following steps:

[0066] The communication architecture consisting of the power consumption information collection main station - terminal (power consumption information collection terminal) - CCO (HPLC carrier master node) - STA (HPLC carrier slave node) - electric energy meter remains consistent with the current technical solution. The terminal has newly integrated Beidou timing chip and long-wave timing chip, and expanded the software protocol to complete the ability to obtain the current time from the telecommunications base station. At this time, the clock sources of the terminal equipment include the power consumption information collection main station (S1), Beidou timing (S2), long-wave timing (S3), and telecommunications base station (S4). Four clock signal sources. CCO and STA expand the millisecond perpetual calendar time, and the electric energy meter expansion protocol requests the current time from the superior as soon as possible after power-on. The time synchronization and timekeeping systems of the low-voltage substation collection system are as shown in the attached Figure 1 As shown, the method flow is as follows Figure 2 shown.

[0067] Step 1: The terminal receives various clock signal sources in real time.

[0068] The terminal newly integrates Beidou timing chips (such as Zhongkewei AT9880B and Shenzhen Changyuan Xinda UM220-III), long-wave timing chips (such as Si4734), and expands the software protocol to complete the ability to obtain the current time from the telecommunications base station. In the operating state, the terminal device receives four types of clock signal sources in real time, including the acquisition master station (S1), Beidou timing (S2), long-wave timing (S3), and telecommunications base station (S4).

[0069] Step 2: The terminal recognizes and responds to the master station's timing instruction with the highest priority

[0070] When the terminal detects the time synchronization instruction from the power consumption information collection master station, it synchronizes the time issued by the master station to the clock unit of the terminal according to the highest priority.

[0071] The terminal's multiple clock sources, including Beidou and long-wave timing, especially the strategy of obtaining the time of telecommunications base stations by upgrading software protocols, can obtain high-accuracy backup clock sources without increasing hardware resources, increasing or decreasing investment, and equipment transformation. The terminal uses the clock source of the main station for collecting electricity consumption information as the clock source with the highest priority.

[0072] Step 3: Evaluation and selection of other reliable clock sources

[0073] When the terminal does not detect the time synchronization instruction from the power consumption information collection master station, follow the detailed steps below to evaluate and select other clock sources as reliable clock sources for the terminal's time synchronization clock source.

[0074] Step 3.1 The terminal evaluates and selects a qualified clock source from the Beidou clock source, long-wave clock source, and telecom base station clock source as a reliable clock source based on the clock signal strength and signal stability for seven consecutive days.

[0075] The terminal continuously monitors the signal strength of the Beidou clock source, long-wave clock source, and telecom base station clock source in a 1-minute cycle, and records the signal strength for 7 consecutive days to form a signal strength sequence M1{(t 1， m 11 ), (t 2， m 12 ),(t 3， m 13 )…(t i， m 1i )…(t n， m 1n )}、M2{(t 1， m 21 ), (t 2， m 22 ),(t 3， m 23 )…(t i， m 2i )…(t n， m 2n )}、M3{(t 1， m 31 ), (t 2， m 32 ),(t 3， m 33 )…(t i， m 3i )…(t n， m 3n )}, where t iis the time series, m 1i 、m 2i 、m 3i Corresponding to t i The strength of the three types of signal sources at the moment. At the same time, the terminal continuously monitors and covers the signal strength sequence forward according to the sliding time of 1 day.

[0076] Define the clock signal source stability as:

[0077] in is the average value of the BeiDou clock source signal strength sequence, that is, the average signal strength of the BeiDou clock source within 7 days, and RSD1(j) is the stability of the BeiDou clock source on the jth day;

[0078] in is the average value of the long-wave clock source signal strength sequence, that is, the average signal strength of the long-wave clock source within 7 days, and RSD2(j) is the stability of the long-wave clock source on the jth day;

[0079] Among them is is the average value of the signal strength sequence of the telecom base station clock source, that is, the average signal strength of the telecom base station clock source within 7 days, and RSD3(j) is the stability of the telecom base station clock source on the jth day;

[0080] The terminal can obtain the clock signal source stability RSD1(j) of three types of signal sources for 7 consecutive days according to the slip time of 1 day, i = 1, 2, 3... When the clock signal source is available, and the clock signal source stability RSD1(j) of the previous 7 days is greater than RSD for 7 consecutive days 10 、RSD 20 、RSD 30 (RSD 10 、RSD 20 、RSD 30 are the setting values ​​of three types of signal sources respectively, obtained according to the clock chip parameters and experience), then the signal source is taken as the reliable clock signal source, and the step 3.2 is entered to calculate the standard clock.

[0081] Step 3.2 selects the reliable clock source obtained in 3.1, calculates the sample density and weight of each clock source, and thus calculates the standard clock.

[0082] The terminal obtains the time T of three types of clock sources every 1 minute = {T1, T2, T3}, so the time distance between any two clock sources is defined as

[0083]

[0084] In the formula: i, j = 1, 2, ..., n.

[0085] Define the clock source time sample density as:

[0086] ρ i =N{d ij ≤ε}

[0087] Wherein, N{·} is a function for calculating the number of sample elements that meet the conditions; ε is a clock error control parameter of the clock source.

[0088] Define the standard clock source as:

[0089]

[0090] where ω i is the weight of the Ti clock source, defined as:

[0091]

[0092] When the time distance between a clock source and all other clock sources is greater than ε, ρ i =0,ω i =0, that is, the clock source has no contribution to the final timing clock.

[0093] For example, the trusted clock source times are T1 = 08:00:00, T2 = 08:00:05, T3 = 08:00:07, ε = 3 seconds, d12 = 5 seconds, d13 = 7 seconds, d23 = 2 seconds. ρ1 = 0, ρ2 = 1, ρ3 = 1, ω1 = 0, ω2 = 0.5, ω3 = 0.5, Ts = 08:00:06. If ε = 10 seconds, ρ1 = 2, ρ2 = 2, ρ3 = 2, ω1 = 1 / 3, ω2 = 1 / 3, ω3 = 1 / 3, Ts = 08:00:04.

[0094] Step 4: Synchronize the terminal with other clock sources

[0095] The terminal calculates the time difference between the standard clock and the terminal's local clock unit. If the terminal time difference is greater than 5 minutes, the terminal generates a clock deviation event and reports it to the master station, which then starts the terminal time synchronization.

[0096] If the terminal time difference is less than or equal to 5 minutes and greater than 5 seconds, the standard clock is synchronized to the terminal clock unit. If the terminal time difference is less than 5 seconds, the terminal does not perform any operation.

[0097] Overall, the terminal repeats the signal source evaluation and timing strategy in step 4 in a 1-minute cycle.

[0098] Step 5: Terminal to energy meter timing, such as Figure 3 As shown. (Data Link Layer, Internet of Things)

[0099] Step 5.1 The terminal synchronizes its clock unit time to the CCO in a 1-minute cycle;

[0100] Step 5.2 CCO periodically synchronizes the clock to all STAs in the local low-voltage area through carrier NTB and extended millisecond perpetual calendar. Through the built-in 25MHz crystal oscillator of CCO and STA and the time slot control mechanism between CCO and STA, the millisecond perpetual calendar is extended to maintain the consistency of STA and CCO clocks at high frequency.

[0101] According to the HPLC communication technology standard and dual-mode communication technology standard of State Grid Corporation of China, the beacon timestamp of the original data link layer does not have a specific absolute time value, but is an NTB value realized by a 25MHz crystal oscillator and a carrier circuit, which is equivalent to a counter with a period of 1ms to achieve synchronization and data transmission between CCO and STA.

[0102] Based on this, the millisecond-level perpetual calendar time (year, month, day, hour, minute, second, microsecond) is expanded and defined in the data link layer beacon frame, and the time of synchronizing the terminal to the CCO is periodically sent to the entire network STA in the millisecond-level perpetual calendar format. The STA receives the beacon frame timestamp from the CCO and synchronizes it to the STA's clock, thus achieving absolute time synchronization of the entire carrier network. Figure 4 As shown, the current carrier communication protocol has a beacon timestamp and a reserved field, which can be used to expand the field of the response protocol to achieve the transmission of absolute time.

[0103] This embodiment realizes high-frequency and high-precision absolute time synchronization between CCO and STA without adding hardware. First, through the synchronization time of the data link layer, the influence of network instability factors such as local environmental interference on the clock synchronization accuracy is solved. Second, through the transmission time of the beacon frame of the data link layer, the high-frequency synchronization can be performed with the beacon frame, which solves the problems of low frequency of master station or terminal synchronization based on the application layer, more channel resources occupied, and large concurrency of the master station. Third, by using high-frequency crystal oscillators and protocol expansion, the synchronization accuracy can reach milliseconds, which is higher than the synchronization accuracy of the application layer.

[0104] Step 5.3 STA confirms whether the energy meter is powered off and whether it responds during information interaction with the energy meter. If the interaction is normal, STA compares the timestamp carried by the read energy meter data and calculates the time difference between the energy meter and STA.

[0105] Step 5.4: If the time difference between the energy meter and the STA is greater than 5s, the STA synchronizes its clock to the energy meter clock unit and continues the monitoring and judgment strategy described in step 5.3 according to the interaction frequency between the STA and the energy meter.

[0106] Step 5.5 If the electric energy meter has a power outage or other abnormalities, the electric energy meter will immediately request the current time from STA after it starts and resumes normal operation and completes the settlement-related data processing. After receiving the request, STA synchronizes its clock to the electric energy meter clock unit.

[0107] At this point, the time synchronization and timekeeping capabilities of the low-voltage substation collection system based on multiple clock sources, namely terminal-CCO-STA-electricity meter, have been realized, which greatly reduces the clock patrol, concurrent time synchronization and key call pressure of the power consumption information collection master station for all terminals and electricity meters. At the same time, it also greatly reduces the risk of terminal and electricity meter clock out-of-tolerance and the risk of power spot transaction settlement data errors caused by the low frequency of clock patrol and time synchronization of all terminals and electricity meters by the power consumption information collection master station and unstable clock sources.

[0108] 1. This embodiment proposes to integrate Beidou timing chip and long-wave timing chip on the terminal side, and expand the software protocol to complete the ability to obtain the current time from the telecommunications base station, so as to increase the terminal clock source, improve the reliability and stability of the overall clock source, and reduce the concurrent pressure of patrol and synchronization of the power consumption information collection master station and the pressure of key call.

[0109] 2. This embodiment proposes to give the highest priority to the master station clock source of the power consumption information collection system to ensure that the master station instructions are executed in the first time. At the same time, considering the inconsistency of clock source availability caused by the stability, signal strength and environmental impact of Beidou, long wave and base station time, it is proposed to select a reliable clock source through a stability evaluation method, and a strategy algorithm for calculating the standard clock source is proposed to solve the abnormal and unstable problems that may exist in various clock sources.

[0110] 3. This embodiment proposes a strategy in which the terminal evaluates and synchronizes the clock source periodically and uninterruptedly, and only synchronizes the terminals with an error of 5s to 5min. The 5s lower limit is to reduce unnecessary over-frequency synchronization operations as much as possible within the allowable error range and save system resources. The 5min upper limit is to prevent the risk of abnormal impact caused by abnormal terminal system or abnormal clock synchronization strategy program.

[0111] 4. The terminal-CCO-STA-electricity meter time synchronization mode proposed in this embodiment utilizes the carrier communication units CCO and STA's own crystal oscillator NTB and the extended millisecond perpetual calendar to achieve high-frequency, high-precision time synchronization and punctual operation from the terminal to the electricity meter, solving the problem that the conventional terminal-to-electricity meter time synchronization strategy is that the terminal directly sends broadcast time synchronization or point-to-point time synchronization instructions to the electricity meter, which is greatly affected by network stability and has low frequency and low accuracy of time synchronization.

[0112] 5. The strategy proposed in this embodiment of actively requesting STA time after the electric energy meter is powered on solves the problem of long synchronization period between the system and the terminal for the electric energy meter, and the clock disorder caused by undervoltage of the on-site battery after power outage, which makes it impossible to obtain accurate time immediately after power is restored, thereby greatly reducing data risks.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The time synchronization and time keeping method of the low voltage area acquisition system is characterized by: The following steps are involved: The terminal receives the clock signals from the acquisition master station and other clock sources in real time; When receiving the time synchronization instruction from the acquisition master station, the time issued by the acquisition master station is synchronized to the clock unit of the terminal first, otherwise the next step is executed; Reliability evaluation and selection of other clock sources: The terminal evaluates and selects other clock sources that meet the conditions as reliable clock sources based on the clock signal strength and signal stability for x consecutive days. Based on the selected reliable clock sources, the sample density and weight of each clock source are calculated to obtain the standard clock; Other clock sources are used to calculate the standard clock to align the terminal time; Terminal to energy meter time synchronization: The terminal synchronizes its time to the CCO according to the set period; the CCO periodically synchronizes the clock to all STAs in the local low-voltage area through the carrier NTB and the extended millisecond perpetual calendar, and expands the millisecond perpetual calendar through the built-in crystal oscillator of CCO and STA and the time slot control mechanism between CCO and STA, so as to maintain the consistency of STA and CCO clocks at high frequency; the STA synchronizes the energy meter.

2. The time synchronization and time keeping method of the low voltage area acquisition system according to claim 1 is characterized in that: The other clock sources include Beidou clock source, long-wave clock source, and telecommunication base station clock source; the terminal integrates Beidou timing chip, long-wave timing chip, and telecommunication base station timing chip.

3. The time synchronization and time keeping method of the low voltage area acquisition system according to claim 1 is characterized in that: The specific process of reliability assessment of other clock sources is as follows: Assume that there are three types of other clock sources; the terminal monitors the signal strength of other clock sources for a long time according to the set period, and records the signal strength for x consecutive days to form signal strength sequences M1{(t 1， m 11 ), (t 2， m 12 ),(t 3， m 13 )…(t i， m 1i )…(t n， m 1n )}、M2{(t 1， m 21 ), (t 2， m 22 ),(t 3， m 23 )…(t i， m 2i )…(t n， m 2n )}、M3{(t 1， m 31 ), (t 2， m 32 ),(t 3， m 33 )…(t i， m 3i )…(t n， m 3n )}, where t i is the time series, m 1i 、m 2i 、m 3i Corresponding to t i The strength of the three types of signal sources at the moment. At the same time, the terminal continuously monitors and covers the signal strength sequence forward according to the slip time of the set period; The clock signal source stability is defined as: in is the average value of the signal strength sequence of the first-class clock source, RSD1(j) is the stability of the first-class clock source on the jth day; in is the average value of the signal strength sequence of the second type of clock source, RSD2(j) is the stability of the second type of clock source on the jth day; Among them is is the average value of the signal strength sequence of the third type of clock source, RSD3(j) is the stability of the third type of clock source on the jth day; The terminal can obtain the clock signal source stability RSD1(j) of the three types of signal sources for x consecutive days every day according to the set period slip time, i = 1, 2, 3...; when the previous clock signal source is available and the clock signal source stability of the previous x days is greater than the set values ​​of the three types of signal sources for x consecutive days, the signal source is taken as a reliable clock signal source.

4. The time synchronization and time keeping method of the low voltage area acquisition system according to claim 3 is characterized in that: The specific process of calculating the standard clock of other clock sources is as follows: Assume that there are three types of reliable clock signal sources; the time T = {T1, T2, T3} of the three types of clock sources obtained by the terminal according to the set period, then the time distance between any two clock sources is defined as Where: i, j = 1, 2, ..., n; Define the clock source time sample density as: ρ i =N{d ij ≤ε}, where N{·} is a function for calculating the number of sample elements that meet the conditions; ε is the clock error control parameter of the clock source; Define the standard clock source as: where ω i is the weight of the Ti clock source, defined as: When the time distance between a clock source and all other clock sources is greater than ε, ρ i =0,ω i =0, that is, the clock source has no contribution to the final timing clock.

5. The method for synchronizing and keeping time of a low voltage area acquisition system according to any one of claims 1 to 4, characterized in that: STA synchronizes the energy meter as follows: STA confirms whether the meter is powered off and responding during information exchange with the meter. If the interaction is normal, STA compares the timestamp carried by the meter data and calculates the time difference between the meter and STA. If the time difference between the energy meter and the STA is greater than 5s, the STA synchronizes its clock to the energy meter clock unit and continues the monitoring and judgment strategy in the previous step according to the interaction frequency between the STA and the energy meter; If the electric energy meter has a power outage or other abnormalities, the electric energy meter will immediately request the current time from the STA after it starts and resumes normal operation and completes the settlement-related data processing. After receiving the request, the STA will synchronize its clock to the electric energy meter clock unit.

6. The low voltage area acquisition system time synchronization and time keeping system is characterized by: include: Signal acquisition module: The terminal receives and acquires clock signals from the master station and other clock sources in real time; Acquisition master station to terminal time synchronization module; When receiving the time synchronization instruction from the acquisition master station, the time issued by the acquisition master station is synchronized to the clock unit of the terminal first; Reliability evaluation and selection module for other clock sources: The terminal evaluates and selects other clock sources that meet the conditions as reliable clock sources based on the clock signal strength and signal stability for x consecutive days; Based on the selected reliable clock sources, the sample density and weight of each clock source are calculated to obtain the standard clock; Other clock sources for terminal time synchronization module: other clock sources calculate the standard clock for terminal time synchronization; Terminal to electric energy meter timing module: The terminal synchronizes its time to CCO according to the set period; CCO periodically synchronizes the clock to all STAs in the local low-voltage area through carrier NTB and extended millisecond perpetual calendar, and expands the millisecond perpetual calendar through the built-in crystal oscillator of CCO and STA and the time slot control mechanism between CCO and STA, so as to maintain the consistency of STA and CCO clocks at high frequency; STA synchronizes the electric energy meter.

7. The low voltage area acquisition system time synchronization and time keeping system according to claim 6 is characterized in that: The other clock sources include Beidou clock source, long-wave clock source, and telecommunication base station clock source; the terminal integrates Beidou timing chip, long-wave timing chip, and telecommunication base station timing chip.

8. The low voltage area acquisition system time synchronization and time keeping system according to claim 6 is characterized in that: The specific process of reliability assessment of other clock sources is as follows: Assume that there are three types of other clock sources; the terminal monitors the signal strength of other clock sources for a long time according to the set period, and records the signal strength for x consecutive days to form signal strength sequences M1{(t 1， m 11 ), (t 2， m 12 ),(t 3， m 13 )…(t i， m 1i )…(t n， m 1n )}、M2{(t 1， m 21 ), (t 2， m 22 ),(t 3， m 23 )…(t i， m 2i )…(t n， m 2n )}、M3{(t 1， m 31 ), (t 2， m 32 ),(t 3， m 33 )…(t i， m 3i )…(t n， m 3n )}, where t i is the time series, m 1i 、m 2i 、m 3i Corresponding to t i The strength of the three types of signal sources at the moment. At the same time, the terminal continuously monitors and covers the signal strength sequence forward according to the slip time of the set period; The clock signal source stability is defined as: in is the average value of the signal strength sequence of the first-class clock source, RSD1(j) is the stability of the first-class clock source on the jth day; in is the average value of the signal strength sequence of the second type of clock source, RSD2(j) is the stability of the second type of clock source on the jth day; Among them is is the average value of the signal strength sequence of the third type of clock source, RSD3(j) is the stability of the third type of clock source on the jth day; The terminal can obtain the clock signal source stability RSD1(j) of the three types of signal sources for x consecutive days every day according to the set period slip time, i = 1, 2, 3...; when the previous clock signal source is available and the clock signal source stability of the previous x days is greater than the set values ​​of the three types of signal sources for x consecutive days, the signal source is taken as a reliable clock signal source.

9. The low voltage area acquisition system time synchronization and time keeping system according to claim 8, characterized in that: The specific process of calculating the standard clock of other clock sources is as follows: Assume that there are three types of reliable clock signal sources; the time T = {T1, T2, T3} of the three types of clock sources obtained by the terminal according to the set period, then the time distance between any two clock sources is defined as Where: i, j = 1, 2, ..., n; Define the clock source time sample density as: ρ i =N{d ij ≤ε}, where N{·} is a function for calculating the number of sample elements that meet the conditions; ε is the clock error control parameter of the clock source; Define the standard clock source as: where ω i is the weight of the Ti clock source, defined as: When the time distance between a clock source and all other clock sources is greater than ε, ρ i =0,ω i =0, that is, the clock source has no contribution to the final timing clock.

10. The low voltage area acquisition system time synchronization and time keeping system according to any one of claims 6 to 9, characterized in that: STA synchronizes the energy meter as follows: STA confirms whether the meter is powered off and responding during information exchange with the meter. If the interaction is normal, STA compares the timestamp carried by the meter data and calculates the time difference between the meter and STA. If the time difference between the energy meter and the STA is greater than 5s, the STA synchronizes its clock to the energy meter clock unit and continues the monitoring and judgment strategy in the previous step according to the interaction frequency between the STA and the energy meter; If the electric energy meter has a power outage or other abnormalities, the electric energy meter will immediately request the current time from the STA after it starts and resumes normal operation and completes the settlement-related data processing. After receiving the request, the STA will synchronize its clock to the electric energy meter clock unit.

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